Abstract
The spectral properties of 5nm size of bare CdSe and (CdSe)ZnS core–shell quantum dots (QDs) have been recorded and investigated under different solvent environments with different polarities and different concentrations. The results showed that the spectral profile of absorption did not change for both quantum dots in different solvents under a wide range of concentrations. On the other hand, the photoluminescence (PL) spectra of (CdSe)ZnS core–shell quantum dots in non-polar solvents showed two bands; the primary around 420nm and the secondary around 620nm. In contrast, the PL spectra of bare CdSe in non-polar solvents, showed a very strong band around 590nm, with a total absence of the primary wavelength band at 420nm. Under high polar solvent environments, bare CdSe showed a new peak around 420nm, which was totally absent in non-polar solvent. Therefore, the solvent plays an important role in the PL spectra of bare CdSe and (CdSe)ZnS core–shell quantum dots.